According to this xda post the Elephone P6000 Pro stock ROM is vulnerable to Stagefright. A Stagefright detector app confirmed this on my phone.
The Post links to this patch, but also mentions that ...

My HTC One M7 has been notifying me about a new update (v 7.18.111.35, Android Security Patch for libstageFright) for the past few months. And every time I try to install it, this is the result:
All ...